Xcode Help Please

I just got Xcode, i looked at the other posts, but they all seem to be old verions. I am having trouble with alot of things. First, when i was on windows, i used "cout << "whatever";" for C++ to display my message. In Xcode, it says that it cannot be used. When i actually build a program that it can run on C++, it doesn't run, but says that it ran as expected, even though no window opened. Please help me.